东天山地区韧剪带石英超微组构分析

通过透射电镜研究，对东天山地区五大韧剪带糜棱岩石曲矿物的超微组构进行了鉴定，并统计了自由位错密度亚颗粒粒径，动态重结晶颗粒粒径等参，获得了各韧剪带的古差异流动力应力。古 力值揭示出了各剪强度变化的规律，即从韧中心到外带，韧宵渐减不上，同时也显出各个韧

A STUDY OF ULTRAMICRO STRUCTURE OF QUARTZ IN THE DUCTILE SHEAR ZONES IN THE TIANSHAN BELT, XINJIANG

The ultramicro structrues in quartz of mylonites from the five large scale ductile shear zones in the Eastern Tianshan have been studied in detail by the transmission eletron microscope method. The authors determined systematically three parameters in quartz of mylonites, that is, denity of free dislocation line, subgrain size and dynamically recrystallized grain size and obtained the differential flow paleostresses during ductile shear deformation for each ductile shear zone. The paper reported a new uitramicro fabrics: vibration structure that was maybe resulted from an impact event. Results suggested that the intensity of ductile shear deformation or defferential flow stress value decreases gradually and length of free dislocation line, subgrain size and dynamically recrystallized grain size and increase regularly from central zone to outer zone in a ductile shear zone. In the five shear zones of the Eastern Tianshan, the central part of the Kanguer zone has the biggest differential flow stress value (222 MPa), the Southern Tianshan zone has the second (194 MPa), the Northern margin of the middle Tianshan has the third (146 MPa); the Yamansu zone has the fouth(135 MPa) and the Harlike zone has the smallest differential flow stress (97 MPa). The differential flow stress values indicatie that the ductile shear zones in the Eastern Tianshan were formed in a depth of middle lower crust, mainly in the depth of 15 20km, belonging to feldspar quartz facies ductile deformation related to plate subduction from north to south, collision and intracontinental deformation during late Paleozoic.